Abstract: A typical hydrothermal synthesis was employed to prepare titania nanotubes (TNTs) with anatase crystal structure using P25 as a raw material. The effects of hydrothermal reaction temperature, calcination temperature on the morphology and crystal structure of TNTs were investigated. CdS quantum dots (QDs) formed in situ were assembled onto the surfaces of TNTs to form CdS/TNTs nanocomposite photocatalyst by using bifunctional organic linker, thiolactic acid. The effects of thiolactic acid concentration on the loading amount of CdS QDs and photoactivity of CdS/TNTs nanocomposite were also studied. The results indicated that when the hydrothermal reaction and calcination temperatures were 150 and 400 ºC, respectively, TNTs have anatase crystal structure with following unique properties, an average diameter of about 8–10 nm, the length of several hundred nanometers with uniform inner and outer diameter along the length direction, tube wall with multilayer structure of about 2–3 nm. After modification with CdS QDs, the absorption of CdS/TNTs nanocomposite in visible light area was enhanced greatly, compared with that of TNTs. The absorption edge of CdS/TNTs was extended to 580 nm. The CdS/TNTs exhibited excellent photocatalytic performance for RhB degradation under visible light irradiation simulated by halogen tungsten lamp.

Key words: titania, nanotube, photocatalyst, cadmium sulfide, quantum dot, rhodamine B, 2-thiolactic acid, degradation